Then, as one door opened, people screamed and the crowd rushed forward. Within seconds, more doors opened. In about five minutes, the boisterous crowd of hundreds had vanished inside to hunt for bargains.

The scene repeated itself throughout Southern California as two of the biggest retail chains -- Best Buy and Macy's, and malls housing their stores -- opened their doors to long lines of shoppers Friday morning.

But for thousands of shoppers, Black Friday had been going on for hours. A growing list of retail chains, including Target and Wal-Mart, began introducing their holiday deals Thursday starting at about 8 p.m.

This year was believed to be the earliest start yet to the shopping spree. Sales are expected to continue through the weekend, and then online retailers are set for their traditional "Cyber Monday."

At Lakewood Mall, which opened at midnight, a frenzy occurred outside the Aeropostale clothing store, where hundreds -- mostly pre-teens -- had lined up for half-price sweatpants and T-shirts.

Down the way, a more controlled but equally large crowd filed into GameStop, where many said they hoped to purchase the Xbox package deal for about $250.

A mob of hundreds of shoppers poured into Macy's only to find a few ups and downs getting what they sought. Just four minutes into Black Friday, the department store's main escalator broke; shoppers traveling up from the ground level let out a scream as the stairs briefly jerked backward and came to a halt.

About two minutes later, the escalator was converted into a staircase, with workers pleading with shoppers to walk, not run, to the second floor.

"We do have an elevator," one employee said as he marveled at the mob crowded around the broken escalator. "But then again, tonight is definitely not the night you'd want to end up stuck in it."